Multiple sets of solutions for harmonic elimination PWM bipolar waveforms: analysis and experimental verification

Abstract

Abstract-Multiple sets of solutions for the selective harmonic elimination pulse-width modulation method for inverter control exist. These sets present an independent solution to the same problem but further investigation reveals that certain sets may offer an improved overall harmonic performance. In this paper, a minimization method is discussed as a way to obtain these multiple sets of switching angles. A simple distortion harmonic factor that takes into account the first two most significant harmonics present in the generated waveform is considered in order to evaluate the performance of each set. The bipolar waveform is thoroughly analyzed and two cases are considered; single-phase patterns which eliminate all odd harmonics and three-phase counterparts which eliminate only the nontriplen odd harmonics from the line-to-neutral pattern but such harmonics are naturally eliminated from the line-to-line waveform. Experimental results support the theoretical considerations reported in the paper. Index Terms-Selective harmonic elimination pulse-width modulation (SHEPWM).

Harmonic Elimination in Three-Phase Voltage Source Inverters by Particle Swarm Optimization

“…As the 3 rd harmonic and other triplen harmonics do not exist when the neutral point is isolated , n takes the odd values 5,7,11,13,17,19, and 23.…”

“…The main challenge associated with the SHE technique is how to obtain analytical solutions of the nonlinear transcendental equations that contain trigonometric terms [5]. Traditional analytical methods for solving the SHE problem are conducted based on the Newton Raphson method.…”

A VSC transmission system using flying capacitor multilevel converters and selective harmonic elimination PWM control

“…Many algorithms have been proposed to deal with this problem. They rely either on the starting values to obtain the exact solutions [13]- [16], or introduce a relatively complicated method to ensure convergence and finding all sets of solutions through a sequential homotopybased computation [17], use of resultant theory, and high-order polynomials [18], and a minimization technique combined with a random search and biased pattern for the initial values applied directly to the set of the transcendental equations [19], [20].…”

A Novel Pulse-Width and Amplitude Modulation (PWAM) Control Strategy for Power Converters

“…Under this condition, the main object of the control strategy is to generate a switching pulse pattern in such a way that a desired output fundamental is produced while specific selective harmonic levels are eliminated or mitigated. This PWM strategy is called Selective Harmonic Elimination/Mitigation Pulse Width Modulation (SHE/M-PWM) [3]- [9] [12]- [16]. It requires finding a solution to a set of nonlinear transcendental equations.…”